Survival of the Species by
romaine24 Draco approaches Harry on the 9 ¾ platform, after their sons have boarded the Hogwarts Express, and invites him over for tea. The discussion they have leads them on an adventure that neither could have expected. HPDH compliant.
If Mpreg isn't your thing then this isn't for you, but otherwise I'd highly advise you read this as soon as humanly possible. It's longish, plotty, full of adventure and kids and dragons, and it has a lovely happy ending.